Prepare Your Mare for Breeding

Although your mare isn't cycling now, the care you give her today will ready her for conception in the months to come

We have a good way to go yet before spring arrives, but if you are thinking of breeding your mare this year, there are a few things you should be doing in preparation.

Your mare may seem perfectly healthy, but a breeding soundness exam by your vet is a good idea. If there’s a problem, finding it well in advance of breeding season will give you time to correct it. Whether or not your mare has foaled before, your veterinarian will check for any injuries or weaknesses along the reproductive tract. If she’s an older mare, the vet may recommend a uterine biopsy to make sure the lining of the uterus is in good shape to support a pregnancy.

A breeding soundness examination can usually be done right on your farm or ranch. It rarely requires tranquilization, but it is important that the mare be under adequate physical restraint at all times.

The vet will inspect the mare’s external genitals to make sure nothing would predispose her to infections. Most common are conformation problems that cause the lips of the vulva to sit on a tilt or incline rather than perpendicular to the ground. Such a condition leads to soiling of the vulva, which in turn can cause infection in the vagina and uterus. Some mares also tend to suck air into the vagina when they move, or pool urine on the vaginal floor, which can also lead to uterine infections.

A simple surgical procedure, called a Caslick’s suture, is often done to help prevent infections. With the mare standing quietly sedated and using local anesthesia, the upper portion of the vulva is sewn shut to seal out contamination. This would be done after any infection has been treated and cleared, and after the mare has been confirmed in foal. Your vet will reopen the closed area as your mare’s foaling time draws near.

After visually examining your mare, your vet will perform a rectal exam, which allows him to palpate her ovaries, uterus and cervix. There won’t be much going on in the ovaries in the late fall and winter, since the mare is not cycling. However, your vet will be able to check for any abnormalities like tumors, an enlarged uterus (which could indicate infection), and that the cervix is of normal length and size. He’ll also note whether the cervix moves freely and is not tied down by any scarring that could indicate previous damage.

Ultrasound of the ovaries, uterus and cervix can also be done by introducing a small ultrasound probe into the rectum. The image, which looks like a black and white X-ray, is viewed on a screen – just like ultrasounds of human babies in the womb. The vet then has a more detailed view of these organs and what is going on inside them.

Your vet may also do a speculum exam of the vagina. This allows him to check for pooling of urine, inflammation, and that the cervical opening looks normal.

Your mare’s udder should also be examined to make sure she has no injuries to the teats or glands themselves, no evidence of inflammation/infection or scarring – things that could interfere with her ability to effectively nurse the foal.

If the breeding farm wants a uterine culture done to confirm that your mare has no infections, your vet may return closer to breeding time, when your mare starts cycling again, to perform that. If the winter exam indicates an infection, your vet may want to administer drugs to start her cycling earlier. That way the mare’s cervix will open up and the necessary cultures and treatments can be done to clear up her problem before breeding season arrives.

The Nutrition Factor
Nutrition is extremely important to fertility and normal cycling. It’s best to keep your mare a bit on the light side (but not thin) through fall and early winter. Start feeding more in late winter and as spring approaches so that she is slowly gaining weight. Mares that are easy keepers and tend to get obese can have fertility problems.

Homegrown: The Financial Reality

Having a foal always sounds like a wonderful idea. It may even be appealing to you as a way to get another horse with a minimum investment. However, make sure you’ve really thought it through. You may be surprised at how much cost is associated with getting a foal on the ground.

Breeding expenses: First, your mare will need a breeding soundness exam, and some farms require a negative uterine culture before they will accept the mare. You may also be asked to provide proof of vaccinations, often for diseases that you might not have routinely vaccinated for before (e.g., strangles, rhinopneumonitis).

There is also the matter of the stud fee. Some up-front money is usually due to the breeder, either a partial stud fee or a booking fee. Both are usually nonrefundable even if the mare does not produce a foal.

You will also have shipping costs, either in getting the mare to the stud farm or of having the semen transported. If you use shipped semen, there will be vet fees for monitoring her cycle and for inseminating the mare. If your mare is going to stay on the breeding farm, there will be daily board, of course.

You will also pay vet costs related to palpations, ultrasound exams, and any drugs that may be used to help time ovulation. If she’s on the farm at a time of one of their routine de-wormings, she’s going to be included. There may be other costs associated with sending your mare to a stallion station, such as “chute fees.”

Pregnancy expenses: You’ll want a vet visit to confirm that your mare is actually pregnant. This is often done 14 to 18 days after breeding while the mare is still at the stud farm. Checks after this are optional, but it’s usually recommended to repeat the exam at one to two months to make sure she didn’t lose the pregnancy – and while there’s still time in the season to rebreed.

If the mare has a conformation problem with her vulva, she may require a Caslick’s surgery to protect the uterus from infection. You’ll need the vet to reverse that surgery when the mare gets close to foaling.

Pregnant mares also need more protein and minerals in their diet to “build” the foal, and in amounts that are higher than their need for increased calories. That means her diet will likely have to be supplemented.

If the mare is going to be exposed to many horses coming and going, your vet may recommend special vaccination protocols. Serious health problems aren’t too common, but some pregnant mares experience laminitis or colic.

Foaling: This really should be attended by someone experienced, preferably your vet. The farm call will be money well spent, for on-the-spot help with delivery, an examination of the baby and mare for any problems, and solid advice on what to look for in the critical early period of the foal’s life.

The first year: Foals and weanlings need much more intensive de-worming than older horses. The initial vaccination series will include at least two vaccinations for each disease, so double the vet visits for that too. Developmental orthopedic problems, such as physitis or contracted tendons, can occur, and be sure to keep a little money aside for injuries.

Routine hoof care is very important, and should start at an early age. Your baby will go through at least two or three halter sizes during this period too. If you have a colt, castration is usually done in the fall or early winter of his first year.

From the age of a year on, just figure your horse expenses will be doubled. If you are relatively inexperienced, you will probably need the services of a professional trainer to get your young horse started in the right direction.

Many vitamins and minerals influence fertility. Keep your mare on a high-quality vitamin and mineral supplement over the winter and into breeding time. Her supplements should correct the specific deficiencies and imbalances in your pasture and hay, so get professional advice on this from an independent source (your vet, a nutritionist, your agricultural extension agent – not from someone selling supplements).

If your mare is overweight, start her on a regular exercise program, lunging when you don’t have time to ride. Cut out the grain, and feed her a 10% to 30% protein pelleted mineral supplement instead. These are fed at 1 to 2 lbs./day, so you can substitute it at times you would normally grain.

If your mare is too thin, be sure her de-worming is up-to-date, including treatment for bots and tapeworms. Feed her free-choice hay and up to 5 lbs./day of a high-quality supplemented grain.

If you are exercising her, you may need to feed more grain. If the mare has a lot of trouble coming up to a normal weight despite being fed amounts that would easily cause another horse to gain, you need to let your vet know so he can look for an underlying medical problem.

Advance Planning
Use the winter to carefully investigate stallion prospects. Once you have selected a stallion or two, contact the breeding farm and make sure you understand the requirements for incoming mares: vaccinations, health certificates, uterine cultures, Coggins, etc. Talk to your vet about scheduling any needed tests and vaccines well in advance of the time you would like to breed your mare.

If your mare is going to need vaccinations that are not part of your normal routine, she will likely have to have two injections, two to four weeks apart, to complete the series. Culture results can take a week or two to come back and Coggins tests have been known to get lost, so be sure to allow enough time to have all your preparations done comfortably ahead of breeding.

Go over your breeding contract carefully and make sure you understand the terms and fees.

Most contracts require payment of the stallion fee only if the mare successfully delivers a live foal. However, the way a live foal is defined can vary. In some, it’s any foal that even takes a breath. Others specify a foal that successfully stands and nurses.

A non-refundable booking fee may be required, even when the actual stud fee isn’t due until she foals. Other contracts call for the breeding fee at time of breeding, with either a refund if there’s no live foal or free rebreeding so that you can try again.

It’s also important to fully understand any other costs associated with having your mare bred, such as ultrasound charges and “chute fees.”

Timing Conception and Birth
Finally, give some thought to when would be the ideal time for the foal to be born. In general, you want to pick a time when weather in your area is comfortably warm and grass is growing well. Pregnancy runs roughly 11 months, so aim for a June breeding for a May foal, etc.

For the best chance of conception, the mare should be cycling regularly at the time she is bred. By late February and into March, your mare’s ovaries will begin producing follicles and eggs again, but she won’t show regular cycling until April or even May and will reach peak natural fertility in June.

Begin watching your mare’s behavior closely for signs of estrus (“heat”) in March and record what you see on a calendar. You’ll notice your mare holding her tail slightly cocked and/or off to the side, frequent urination, and “winking” – repeatedly opening and closing the lips of the vulva. These signs will gradually become more obvious as you get into spring, and will normally settle into a pattern of two to five days of estrus behavior, separated by two to 2½ weeks of being out of estrus. Knowledge of your mare’s normal pattern and timing is extremely useful for the breeder to know.

Handling the Mare

Since most veterinarians wrap mare’s tail before palpating and inseminating, it wouldn’t hurt to rehearse this a number of times so she becomes accustomed to it.

Unless you make cleaning your mare’s udder and vaginal/anal area part of your regular routine, she may be startled by the reproductive examination and breeding procedures. This is especially true of mares who have never been bred, and is made worse by the fact you’re working behind the mare, where she can’t easily see you. It is potentially dangerous to both the mare and the people trying to work with her.

You can help her become more relaxed about the idea by gently washing around her anus, vulva and udder with a towel dipped in warm water. Just be sure to have someone at her head the first few times you attempt this. It’s also a good idea to get her used to having her tail wrapped. Wrap a regular polo or cotton leg wrap snugly, but not too tightly, around her tailbone. Leave it on for a few minutes, then remove the wrap.

If you want to breed your mare to foal early in the year, you may want to consider keeping her inside under lights over the winter to mimic a daylight period of at least 12 hours per day. Your vet can give you specific guidelines for this, but in general you should begin the light exposure Dec. 1 so that you can “trick” your mare’s body into thinking that it’s spring.

With the help of lights, most mares will be having good cycles and ovulating predictably by February. But keep in mind that your mare may also need to be kept blanketed because the artificial light may also cause her to shed her winter hair.

Another option is for your vet to manipulate ovarian activity with drugs. There are several different ways this can be helpful. Your vet can get your mare cycling earlier by the use of hormones. He can devise a plan to synchronize her cycle around a time when it’s convenient for you to ship her. He can even use injections to influence when she will ovulate, which increases the odds that she will become pregnant.

Whether you choose to intervene in her cycle or let nature take its course, it is a good idea to have your vet check your mare’s ovaries starting at least a month before the desired breeding time. This also allows him to tell you when she is likely to ovulate and when you should plan your stallion visit.

You have a lot to think about, a lot of planning and preparation, but getting it right is worth the effort. A year is a long time to wait to try again. With a little preparation to make sure your mare is in the best general and reproductive condition, and keeping your vet involved in the process, your chances of a successful breeding will be as good as they can be. PH*

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